This invention relates to a hair cosmetic composition excellent in the effect of improving optical or mechanical properties of hair.
A variety of hair cosmetic compositions containing cationic surfactants have been used for many years to improve optical or mechanical properties of hair, such as luster, softness, body and the like. Effects of these hair cosmetic compositions are however either temporary or insufficient.
JP 10-236927 A discloses a hair treatment composition for supplying a precursor of a hair-united lipofatty acid to hair follicles, in which (i) a first fatty acid precursor selected from leucine, isoleucine, methionine or valine, (ii) a second fatty acid precursor selected from a saccharide or a mono-, di- or tri-carboxylic acid and (iii) an anionic, amphoteric or cationic surfactant has been added. However, this invention was created by drawing a hint from the fact that the above-described components (i) and (ii) act as a precursor of a hair-united lipofatty acid for hair follicles. It is therefore impossible to predict from this invention what components should be added for the improvement of optical or mechanical properties of hair.
The present invention therefore has as an object the provision of a hair cosmetic composition excellent in the effect of improving optical or mechanical properties of hair.
The present inventors have found that combined use of glycine or alanine and a specific acid compound with an cationic surfactant makes it possible to obtain a hair cosmetic composition excellent in the effect of improving optical or mechanical properties of hair such luster, softness, body and the like.
This invention therefore provides a hair cosmetic composition comprising (A) glycine or alanine, (B) an xcex1-hydroxy acid, xcex2-hydroxy acid, 1,2-dicarboxylic acid, 1,3-dicarboxylic acid or aromatic carboxylic acid, and (C) a cationic surfactant.
The component (A) for use in the present invention is glycine or alanine. Of these, particularly preferred are glycine and xcex1-alanine.
As the component (A), glycine and alanine may be used in combination. The component (A) may be added preferably in a proportion of from 0.01 to 20 wt. %, more preferably from 0.05 to 10 wt. %, notably from 0.1 to 5 wt. % based on the whole composition from the standpoint of imparting color deepness to hair.
Among acids usable as the component (B) in the present invention, illustrative xcex1-hydroxy acids and xcex2-hydroxy acids can include glycolic acid, lactic acid, methylacetic acid, mandelic acid, 4-hydroxymandelic acid, 3-hydroxy-4-methoxymandelic acid, 4-hydroxy-3-methoxymandelic acid, 3-(2-hydroxyphenyl)lactic acid, 3-(4xe2x80x2-hydroxyphenyl)lactic acid, 3,4-dihydromandelic acid, glyceric acid, malic acid, tartaric acid, and citric acid.
Further, illustrative 1,2-dicarboxylic acids and 1,3-dicarboxylic acids can include malonic acid, succinic acid, maleic acid, and fumaric acid. Illustrative aromatic carboxylic acids can include benzoic acid, phthalic acid, and salicylic acid.
Among these, malic acid, succinic acid and maleic acid are particularly preferred.
As the component (B), one or more of the above-described acids can be used. The component (B) may be added preferably in a proportion of from 0.01 to 5 wt. %, more preferably from 0.05 to 3 wt. %, notably from 0.1 to 2 wt. % based on the whole composition from the standpoint of imparting transparency to hair.
The cationic surfactant for use as the component (C) in the present invention can be, for example, a quaternary ammonium salt represented by the following formula (1): 
wherein at least one of R1, R2, R3 and R4 represents an alkyl or alkenyl group, which may optionally be substituted by one or more alkoxy, alkenyloxy, alkanoylamino or alkenoylamino groups and has 8 to 28 carbon atoms in total, the remaining one or ones each independently represent a benzyl group, an alkyl or hydroxyalkyl group having 1 to 5 carbon atoms or a polyoxyethylene group having a total added mole number not greater than 10, and Zxe2x88x92 represents a halogen ion or an organic anion.
Among such quaternary ammonium salts, preferred are those represented by the formula (1) in which one or two of R1, R2, R3 and R4 each independently represent a linear or branched alkyl group having 12 to 24 carbon atoms or a benzyl group, the remaining ones each independently represent a methyl group, and Zxe2x88x92 represents a halogen ion; and particularly preferred as those represented by the formula (1) in which one of R1, R2, R3 and R4 represents a linear or branched alkyl group having 12 to 22 carbon atoms, the remaining ones each independently represent a methyl group, and Zxe2x88x92 represents a halogen ion.
These cationic surfactants may be used either singly or in combination. The cationic surfactant may be added preferably in a proportion of from 0.1 to 20 wt. %, more preferably from 0.2 to 10 wt. %, notably from 0.5 to 5 wt. % based on the whole composition from the standpoint of imparting softness to hair.
To the hair cosmetic composition according to the present invention, (D) a higher alcohol can be added further. This higher alcohol can improve the touch of hair further.
Examples of the higher alcohols are those having 6 to 30 carbon atoms, with 8 to 22 carbon atoms being preferred. Further, those having melting points not higher than 55xc2x0 C. are preferred.
Such higher alcohols may be used either singly or in combination. The higher alcohol is added in a proportion of from 3 to 10 molar times, preferably from 4 to 8 molar times of the cationic surfactant added as the component (C).
To the hair cosmetic composition according to the present invention, (E) a silicone can be added further. This silicone can provide hair with nongreasiness.
Preferred examples of the silicone are methyl-polysiloxanes represented by the following formula (2): 
wherein R5 represents a methyl or phenyl group, R6 represents a methyl or hydroxyl group, and m stands for a number of from 100 to 2,000.
These silicones may be used either singly or in combination. The silicone may be added preferably in a proportion of from 0.01 to 10 wt. %, more preferably from 0.05 to 10 wt. %, notably 0.1 to 5 wt. % based on the whole composition.
To the hair cosmetic composition according to the present invention, surfactants other than those described above, cationic polymers, cosmetic oils, dyes, reducing agents, oxidizing agents, metal chelates, antioxidants, viscosity modifiers, preservatives, animal and plant extracts, antiphlogistics, disinfectants, antidandruff agents, oxidation inhibitors, pearlants, ultraviolet absorbers, pH regulators, colors, solvent, perfumes and the like can be added as desired in addition to the above-described components.
The pH of the hair cosmetic composition according to the present invention may preferably be not higher than the pKa of the xcex1-hydroxy acid (B) employed, and may range specifically from 2 to 6, with pH 2.5 to 3.5 being particularly preferred.
The hair cosmetic composition according to the present invention can be produced by an ordinary method and can be used, for example, as a hair rinse, conditioner, treatment, hair cream, hair pack or the like